There is evidence that suggests that ethyl alcohol influences CNS function by interacting with the lipid components of cerebral membranes, altering transport processes and membrane stability. The proposed experiments will examine the composition, subcellular distribution and metabolism of membrane lipids in the brains of rats chronically treated with alcohol, seeking evidence of adaptive changes that contribute to the development of alcohol dependence and the physical manifestations of the withdrawal state. Rats will receive alcohol by inhalation to produce physical dependence. Brains of dependent and control rats will be fractionated into synaptic plasma membranes, synaptic vesicles, microsomes, mitochondria, and myelin by density gradient centrifugation. The lipid composition of these subcellular fractions will be analyzed by thin- layer chromatographic procedures. Acyl group composition will be determined by gas chromatography. The incorporation of radioactive precursors of lipids will also be studied in these animals. It is hoped that these studies will contribute to an understanding of the biochemical factors underlying alcohol dependence and the withdrawal syndrome.